1. Technical Field
The present invention relates to a method of manufacturing a backlight unit, a backlight unit, an electrooptical device and electronic equipment.
2. Related Art
In a liquid crystal display device, which is an electrooptical device, an optical sheet having a plurality of microlenses is provided in a backlight unit which is embedded in the liquid crystal display device and illuminates the liquid display. With this optical sheet, it is possible to efficiently collect light from a light source in the backlight unit and send it to the liquid crystal elements (picture elements). JP-A-2004-157430 is a first example of related art. There are many reports about a method of forming the microlens by using a droplet discharge method including the first example.
JP-A-2004-309801 is a second example of related art. For example, the second example discloses an edge-light type (side-light type) backlight unit in which a linear lamp is provided as the light source along a side face of a light guide plate. A plurality of the elliptical microlenses having a major axis and a minor axis are formed on a sheet made of synthetic resin and the like. A method of fabricating such microlens by using a metal mold has been proposed.
However, according to such method, there is a limit to the number of the linear lamps which can be embedded with the unit so that enough brightness for the display could not be secured in a case of the large screen. Moreover, it is difficult to make the size of the display device larger because the weight of light guide plate becomes too heavy. For this reason, the liquid crystal panel with the edge-light type backlight unit has a low brightness though unevenness of the brightness in the screen can be reduced. On the other hand, in a case of a backlight unit in which the linear lamps are located immediately below the screen, it is possible to increase the number of the lamps provided therein in order to increase the brightness of the screen according to the size of the screen. However, when the number of the lamps increases, problems of heat and cost could arise.